Background The underlying mechanisms of neuropathic pain remain unclear. This work aimed to investigate the role of Sirtuin3 (SIRT3), an nicotinamide adenosine dinucleotide+-dependent histone deacetylase, in the development of neuropathic pain induced by type 2 diabetes mellitus (T2DM) and to explore the associated mechanisms.
Methods Diabetic neuropathic pain (DNP) in rats was induced by high-fat diet/low-dose streptozotocin. The pain behaviors were examined using the von Frey and Hargreaves tests. The levels of SIRT3, manganese superoxide dismutase (MnSOD) and catalase (CAT) were determined using Western blot and RT-qPCR. The acetylation, phosphorylation and ubiquitination of forkhead box class O3a (FoxO3a) were analyzed by immunoprecipitation and Western blot.
Results SIRT3 expression and activity were significantly reduced in the spinal dorsal horn of DNP model rats. Overexpression of spinal SIRT3 reversed the pain hypersensitivity in the DNP model rats, but knockdown of spinal SIRT3 mimicked the pain effect, eliciting pain hypersensitivity in normal rats. Moreover, overexpression of spinal SIRT3 in DNP model rats increased the FoxO3a level and upregulated the antioxidant genes MnSOD and CAT by deacetylating FoxO3a and inhibiting FoxO3a phosphorylation and ubiquitination. Knockdown of spinal SIRT3 in normal rats decreased the FoxO3a level and downregulated MnSOD and CAT by inhibiting the deacetylation of FoxO3a and further increasing FoxO3a phosphorylation and ubiquitination.
Conclusions These results suggest that, by deacetylating FoxO3a and further reducing its phosphorylation, ubiquitination and degradation in the spinal dorsal horn, SIRT3 stabilizes FoxO3a protein and inhibits oxidative stress, resulting in pain alleviation in T2DM model rats.
- chronic pain
- animal experimentation
- pain perception
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CZ and YZ contributed equally.
Contributors CZ and YW designed the study and generated draft manuscript. YZ and CZ conducted the study and carried out the statistical analysis. XJ, GW and RW helped conduct the study and prepared experimental materials.
Funding This work is supported by the Natural Science Foundation of Jiangsu Province (BK20191464), and the Key Subject of Colleges and Universities Natural Science Foundation of Jiangsu Province (18KJA320008).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Animal care and experimental procedures were approved by the Laboratory Animal Ethics Committee of Xuzhou Medical University (approval number: 201701w002).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
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